a. Technical Field
The present invention relates to an active matrix display device comprising switching elements electrically connected to respective picture element electrodes and to a method of manufacturing the same.
b. Prior Art
Flat panel display devices, typically liquid crystal display devices, having a low profile, are lightweight and consume little power when compared to more conventional display devices. For these reasons, flat panel display devices are being applied in various fields such as display units of personal computers and word processors, TV display devices, and projection display devices.
Particularly desirable are active matrix display devices which comprise switching elements that are electrically connected to respective picture element electrodes. Such active matrix display devices are under intensive research and development because they provide for high-quality display images which are free of cross-talk between adjacent picture elements.
The general architecture of an active matrix liquid crystal display device of, for example, the light transmitting type is now briefly described. Such active matrix liquid crystal display device comprises a liquid crystal composition held between an array substrate and a counter substrate through orientation films. The array substrate comprises a plurality of signal lines and a plurality of scanning lines disposed in a matrix fashion on a glass substrate, with picture element electrodes being arranged through tin film transistors (hereinafter referred to briefly as TFT) provided as switching elements in the vicinity of respective junctions. Additional capacitor lines are also disposed substantially in parallel with the scanning lines on the glass substrate and an insulating film is interposed between the additional capacitor line and the picture element electrode so as to provide an additional capacitor (Cs) between the additional capacitor line and picture element electrode.
The counter substrate comprises a glass substrate having a light attenuating film and a counter electrode disposed thereon, the light attenuating film being oriented in a matrix fashion covering the TFTs and surroundings of the picture element electrodes.
Further, the respective signal lines and scanning lines of the array substrate are electrically connected to a driving circuit board through an FPC (flexible printed circuit) comprising a polyimide or other flexible substrate and metal wirings formed thereon or a TAB (tape automated bonding) comprising a flexible printed circuit board carrying driving elements thereon.
Moreover, the counter electrode of the counter substrate is electrically connected to the array substrate through a transfer comprising a dispersion of electrically conductive particles such as particles of silver in a resin matrix. The counter electrode is further electrically connected to the driving circuit board through, for example, said FPC or TAB.